Flexible zero-carbon power system and use method thereof

Abstract

The invention belongs to the technical field of thermal power generating units, and relates to a flexible zero-carbon power system and a use method thereof. Comprising coal mine drainage water and new energy electricity abandoning; the coal mine drainage water and the new energy abandoned electricity are both connected with the electrolytic hydrogen production device; the electrolytic hydrogen production device is respectively connected with the magnesium-based solid hydrogen storage device and the oxygen storage tank; the oxygen storage tank is connected with the gas mixing device; the mixing device is respectively connected with the fuel conveying device and the boiler; the fuel conveying device is connected with the boiler; the magnesium-based solid hydrogen storage device is connected with the oil-steam heat exchanger; the oil-steam heat exchanger is connected with the steam turbine; the steam turbine is connected with the boiler; resources such as abandoned wind and light, coal mine drainage water and the like can be comprehensively utilized, and low-cost zero-carbon power system construction is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal power units, and relates to a flexible zero-carbon power system and a using method thereof. Background Art

[0002] With the increasing challenges of global climate change, the development of low-carbon and zero-carbon energy has become one of the core tasks of energy transformation. In traditional thermal power generation, especially power generation methods that burn fossil fuels such as coal power and oil power, a large amount of pollutants such as carbon dioxide, sulfur oxides, nitrogen oxides, and particulate matter are released during the production process. The emissions of these greenhouse gases not only directly lead to global warming but also exacerbate air pollution and ecological damage. Therefore, how to effectively reduce carbon emissions while ensuring power supply has become an important issue in the global energy field.

[0003] With the large-scale development and application of new energy sources such as wind energy and solar energy, their power output has strong randomness and intermittency, making it difficult to supply power stably. This requires the power grid to have stronger regulation capabilities to cope with the challenges brought by the volatility of new energy power generation. The growth of power load, the lack of regulation resources, and the rapid construction of new energy in the western region have made the problem of new energy grid connection and consumption more prominent. Especially during the bundled operation of large-scale wind and solar bases and supporting coal power, although coal power, as a regulation and supporting resource, has improved the stability and transmission efficiency of the power grid to a certain extent, its carbon emission problem cannot be ignored and has become an important factor affecting the low-carbon energy transformation. Therefore, how to reduce the carbon emissions of traditional coal power while ensuring power supply has become a technical problem to be solved urgently.

[0004] In addition, mine drainage water is a by-product generated during the coal mining process and usually contains a large amount of water and minerals. The discharge of mine drainage water will cause certain pollution to the environment, especially it may contain harmful substances such as heavy metals. If these drainage waters cannot be effectively treated and utilized, they will have a negative impact on the surrounding ecological environment and water resources. Therefore, how to reasonably recycle and treat mine drainage water through technical means to reduce pollution and improve resource utilization efficiency has become a technical issue to be solved urgently in the coal mining industry. Summary of the Invention

[0005] The purpose of the invention is to solve the problems in the prior art, and provide a flexible zero-carbon power system and a using method thereof, which can comprehensively utilize resources such as abandoned wind and light and mine drainage water to realize the construction of a low-cost zero-carbon power system.

[0006] To achieve the above object, the invention adopts the following technical solutions: In a first aspect, the present invention provides a flexible zero-carbon power system, including mine drainage water and curtailed new energy power; both the mine drainage water and the curtailed new energy power are connected to an electrolytic hydrogen production device; the electrolytic hydrogen production device is respectively connected to a magnesium-based solid-state hydrogen storage device and an oxygen storage tank; the oxygen storage tank is connected to a gas mixing device; the mixing device is respectively connected to a fuel delivery device and a boiler; the fuel delivery device is connected to the boiler; the magnesium-based solid-state hydrogen storage device is respectively connected to the boiler and an oil-steam heat exchanger; the oil-steam heat exchanger is connected to a steam turbine; the steam turbine is connected to the boiler.

[0007] Preferably, the boiler is connected to a preheater; the preheater is connected to a dust collector; the dust collector is connected to a desulfurization tower; the desulfurization tower is connected to a dehydrator; the dehydrator is connected to a shunt device; the first outlet of the shunt device is connected to a CO2 compressor; the CO2 compressor is connected to a liquid CO2 storage tank.

[0008] Preferably, the boiler is connected to an economizer; the economizer is connected to the preheater.

[0009] Preferably, the CO2 compressor is connected to a cooling device; the cooling device is connected to a separation device; the separation device is connected to the liquid CO2 storage tank.

[0010] Preferably, the second outlet of the shunt device and the liquid CO2 storage tank are both connected to the gas mixing device through the preheater.

[0011] Preferably, the magnesium-based solid-state hydrogen storage device is connected to the first inlet of the oil-steam heat exchanger through a first pipeline; the first outlet of the oil-steam heat exchanger is connected to the magnesium-based solid-state hydrogen storage device through a second pipeline.

[0012] Preferably, the second outlet of the oil-steam heat exchanger is connected to the steam turbine through a third pipeline; the steam turbine is connected to the second inlet of the oil-steam heat exchanger through a fourth pipeline.

[0013] Preferably, the liquid CO2 storage tank and the magnesium-based solid-state hydrogen storage device are both connected to a collection device.

[0014] In a second aspect, the present invention provides a method for using a flexible zero-carbon power system, including the following steps: The curtailed new energy power supplies power to the electrolytic hydrogen production device, enabling the electrolytic hydrogen production device to electrolyze the mine drainage water to generate oxygen and hydrogen. According to the boiler load and the co-firing ratio, hydrogen is preferentially supplied to the boiler, and the excess hydrogen is stored in the magnesium-based solid-state hydrogen storage device; when the electrolytic hydrogen production device stops or operates at a low load and the hydrogen produced is insufficient to meet the boiler co-firing demand, hydrogen is released from the magnesium-based solid-state hydrogen storage device to make up for it; the heat required for dehydrogenation of the magnesium-based solid-state hydrogen storage device is provided by extracting high-temperature steam from the steam turbine and heating the heat transfer oil through the oil-steam heat exchanger; the specific dehydrogenation rate is regulated by the temperature and flow rate of the heated heat transfer oil. The generated oxygen is stored in an oxygen storage tank through compression or cryogenic cooling. According to the boiler load demand, the oxygen storage tank supplies oxygen in a timely and quantitative manner, and mixes with the recycled flue gas in a gas mixing device to form primary air and secondary air; the primary air enters the fuel delivery device, carries pulverized coal into the boiler, and the secondary air directly enters the boiler; in the boiler, according to the combustion, load and flue gas characteristics, the amount of hydrogen, primary air volume and secondary air volume participating in combustion are adjusted in real time; hydrogen and pulverized coal in the boiler burn in an oxygen and carbon dioxide atmosphere, generating high-concentration and high-humidity flue gas and discharging it from the economizer. After being cooled by the preheater, it successively enters the dust collector, desulfurization tower and dehydrator, and then becomes dry carbon dioxide; after being split by a splitting device, a part of the carbon dioxide returns to the gas mixing device through the preheater to ensure the demand for circulating air volume, and the other part of the carbon dioxide is compressed, condensed, separated and liquefied and then stored in a liquid CO2 storage tank; the liquid CO2 storage tank is used to supplement the circulating carbon dioxide flow when the primary air volume and secondary air volume increase, and the remaining carbon dioxide is recycled.

[0015] Preferably, the recycled flue gas is carbon dioxide.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses an electrolytic hydrogen production device to electrolyze mine drainage water to produce oxygen and hydrogen by using new energy abandoned electricity. The prepared green hydrogen is used for carbon reduction in thermal power co-firing, and the prepared oxygen is used for oxy-fuel combustion carbon capture. By coupling electrolytic water hydrogen production and oxy-fuel combustion, a low-cost zero-carbon power system is constructed. The liquid CO2 storage tank is used for carbon sequestration or resource utilization (such as methanol production, etc.) on the one hand; on the other hand, when the boiler load increases, it is used to supplement the circulating air volume to meet the variable load demand of the boiler. Through the magnesium-based solid hydrogen storage device, oxygen storage tank and liquid CO2 storage tank, the problem of mismatch between the volatility of new energy abandoned electricity and the variable load operation of the boiler is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic structural diagram of a flexible zero-carbon power system of the present invention.

[0019] Wherein: 1. Mine drainage water; 2. Abandoned electricity of new energy; 3. Electrolytic hydrogen production device; 4. Magnesium-based solid hydrogen storage device; 5. Oil-steam heat exchanger; 6. Steam turbine; 7. Oxygen storage tank; 8. Gas mixing device; 9. Fuel delivery device; 10. Boiler; 11. Preheater; 12. Dust collector; 13. Desulfurization tower; 14. Dehydrator; 15. Shunt device; 16. Compressor; 17. Liquid CO2 storage tank. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0023] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0024] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0025] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and defined, if the terms "set", "installed", "connected", "linked" are used, they should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings: The first object of the present invention is to provide a flexible zero-carbon power system, as Figure 1 shown, including mine drainage water 1 and abandoned new energy electricity 2; both the mine drainage water 1 and the abandoned new energy electricity 2 are connected to the electrolytic hydrogen production device 3; the electrolytic hydrogen production device 3 is respectively connected to the magnesium-based solid hydrogen storage device 4 and the oxygen storage tank 7; the oxygen storage tank 7 is connected to the gas mixing device 8; the mixing device 8 is respectively connected to the fuel delivery device 9 and the boiler 10; the fuel delivery device 9 and the boiler 10 are connected; the magnesium-based solid hydrogen storage device 4 is respectively connected to the boiler 10 and the oil-steam heat exchanger 5; the oil-steam heat exchanger 5 is connected to the steam turbine 6; the steam turbine 6 and the boiler 10 are connected. The present invention uses the abandoned new energy electricity 2 and decomposes the mine drainage water 1 into hydrogen and oxygen through the electrolytic hydrogen production device 3. The magnesium-based solid hydrogen storage device 4 has a high hydrogen storage density and good safety. Compared with the traditional gaseous hydrogen storage method, solid hydrogen storage is safer and more reliable during storage and transportation, and the release and storage of hydrogen are more efficient. The oxygen storage tank 7 is used to store the oxygen generated during the electrolysis of water. Oxygen acts as an oxidizer during the combustion process, which can improve the combustion efficiency, reduce the harmful substances generated by incomplete combustion, and at the same time make full use of the oxygen generated by the electrolysis of water to improve the overall efficiency of the system. The gas mixing device 8 reasonably mixes the stored oxygen and carbon dioxide to ensure the optimal gas ratio during the combustion process, improve the combustion efficiency and stability, reduce emissions, and further promote the application of clean energy. The fuel delivery device 9 transports the mixed gas to the boiler 10, ensuring the efficient delivery of energy after the mixing of carbon dioxide and oxygen, and providing stable and clean energy for the boiler. The boiler 10 uses the gas for heat energy conversion to drive the steam turbine 6 to work. By burning hydrogen and the mixed gas, it can generate high-efficiency and zero-carbon heat energy, reduce the dependence on fossil energy, and ensure the low-carbon operation of the system.

[0027] The boiler 10 is connected to the preheater 11; the preheater 11 is connected to the dust collector 12; the dust collector 12 is connected to the desulfurization tower 13; the desulfurization tower 13 is connected to the dehydrator 14; the dehydrator 14 is connected to the shunt device 15; the first outlet of the shunt device 15 is connected to the CO2 compressor 16; the CO2 compressor 16 is connected to the liquid CO2 storage tank 17. The connection between the boiler 10 and the preheater 11 can utilize waste heat for preheating, reducing heat energy loss and improving energy utilization efficiency, providing better heat energy support for the overall operation of the system. The dust collector 12, desulfurization tower 13 and dehydrator 14 enable the flue gas to undergo multi-stage treatment before discharge, effectively removing solid particles, sulfides and moisture, ensuring that the flue gas discharge meets environmental protection standards and reducing environmental pollution. The connection between the shunt device 15 and the CO2 compressor 16 can shunt, compress and store carbon dioxide in the flue gas. Through the cooperation of the CO2 compressor 16 and the liquid CO2 storage tank 17, the recovery and storage of carbon dioxide can be achieved, which not only helps to reduce greenhouse gas emissions, but also provides conditions for the subsequent utilization of carbon dioxide (such as boosting, sequestration or commercial use).

[0028] The boiler 10 is connected to the economizer; the economizer is connected to the preheater 11. The economizer effectively utilizes the waste heat in the flue gas of the boiler 10 and transfers this waste heat to the boiler feed water, reducing the temperature of the feed water. In this way, when the boiler 10 receives feed water at a lower temperature, it can utilize more heat energy during the combustion process, thereby reducing the demand for fuel and optimizing the combustion efficiency.

[0029] The CO2 compressor 16 is connected to the cooling device, which can effectively reduce the temperature of the CO2 gas during the compression process, avoid the impact of overheating on the equipment, and increase the gas density, providing more stable conditions for subsequent processing; the cooling device is connected to the separation device, and by cooling to reduce the gas temperature, the separation effect of CO2 and impurities is improved, ensuring that higher purity CO2 enters the separation device; the separation device is connected to the liquid CO2 storage tank 17, which efficiently stores the purified CO2 gas in a liquid state for subsequent utilization or sequestration. The entire system optimizes the CO2 treatment process, not only improving the recovery efficiency, but also reducing emissions, with significant environmental and economic benefits.

[0030] The second outlet of the shunt device 15 and the liquid CO2 storage tank 17 are both connected to the gas mixing device 8 through the preheater 11. After being shunted by the shunt device 15, a part of the carbon dioxide returns to the gas mixing device 8 through the preheater 11 to ensure the required circulating air volume. The liquid CO2 storage tank 17 also serves as another source of carbon dioxide and provides carbon dioxide when needed. After flowing out of the storage tank 17, the liquid carbon dioxide is heated to an appropriate temperature by the preheater 11, converted into gaseous carbon dioxide, and transported to the gas mixing device 8 through a pipeline to further supplement the carbon dioxide gas required by the system. In this way, not only can the gas mixing device 8 continuously and stably provide the required carbon dioxide, but also the supply of liquid CO2 can be adjusted to flexibly meet the gas demand under different working conditions.

[0031] The magnesium-based solid hydrogen storage device 4 is connected to the first inlet of the oil-steam heat exchanger 5 through the first pipeline; the first outlet of the oil-steam heat exchanger 5 is connected to the magnesium-based solid hydrogen storage device 4 through the second pipeline. The second outlet of the oil-steam heat exchanger 5 is connected to the steam turbine 6 through the third pipeline; the steam turbine 6 is connected to the second inlet of the oil-steam heat exchanger 5 through the fourth pipeline. The dehydrogenation process of the magnesium-based solid hydrogen storage device 4 requires heat absorption, and the required heat is provided by extracting high-temperature steam from the steam turbine 6 and heating the heat-conducting oil through the oil-steam heat exchanger 5. After heat exchange, the high-temperature heat-conducting oil returns to the oil-steam heat exchanger 5; the specific dehydrogenation rate is regulated by the temperature and flow rate of the heated heat-conducting oil.

[0032] The liquid CO2 storage tank 17 and the magnesium-based solid hydrogen storage device 4 are both connected to the collection device. According to the downstream user situation, the CO2 in the liquid CO2 storage tank 17 of the system of the present invention can be further combined with the hydrogen stored in the magnesium-based solid hydrogen storage device 4 in the collection device to produce e-fuels such as methanol, methane, and aviation kerosene.

[0033] The present invention maximizes the thermal power carbon reduction benefits brought by green power consumption by comprehensively using the hydrogen and oxygen products of electrolytic hydrogen production through two ways of hydrogen-doped combustion and oxygen-enriched combustion. Compared with the pure hydrogen-doped carbon reduction scheme, the power consumption is reduced by 42%. On the other hand, the hydrogen, oxygen, and carbon dioxide storage equipment composed of the magnesium-based solid hydrogen storage device 4, the oxygen storage tank 7, and the liquid CO2 storage tank 17 is used to adjust the mismatch between the volatility of new energy curtailment electricity 2 and the variable load operation of the boiler 10.

[0034] The second object of the present invention is a method for using a flexible zero-carbon power system, including the following steps: The curtailed new energy power 2 supplies power to the electrolytic hydrogen production device 3, enabling the electrolytic hydrogen production device 3 to electrolyze the mine drainage water 1 to generate oxygen and hydrogen. According to the load and blending ratio of the boiler 10, hydrogen is preferentially supplied to the boiler 10, and the excess hydrogen is stored in the magnesium-based solid-state hydrogen storage device 4; when the electrolytic hydrogen production device 3 shuts down or operates at low load and the hydrogen produced is insufficient to meet the blending demand of the boiler 10, the magnesium-based solid-state hydrogen storage device 4 releases hydrogen for supplementation; the heat required for dehydrogenation of the magnesium-based solid-state hydrogen storage device 4 is extracted from the high-temperature steam of the steam turbine 6 and heated by the oil-steam heat exchanger 5 to provide heat transfer oil. After heat exchange, the high-temperature heat transfer oil returns to the oil-steam heat exchanger 5; the specific dehydrogenation rate is regulated by the temperature and flow rate of the heat transfer oil. The generated oxygen is stored in the oxygen storage tank 7 after compression or cryogenic treatment. According to the load demand of the boiler 10, the oxygen storage tank 7 supplies oxygen in a timely and quantitative manner, and mixes with the recycled flue gas (carbon dioxide) in the gas mixing device 8 to form primary air and secondary air; the primary air enters the fuel conveying device 9 and carries pulverized coal into the boiler 10, and the secondary air directly enters the boiler 10; in the boiler 10, according to the combustion, load and flue gas characteristics, the amount of hydrogen, primary air volume and secondary air volume participating in combustion are adjusted in real time; hydrogen and pulverized coal in the boiler 10 burn in an oxygen and carbon dioxide atmosphere, generating high-concentration and high-humidity flue gas and discharging it from the economizer. After being cooled by the preheater 11, it successively enters the dust collector 12, desulfurization tower 13 and dehydrator 14, and then becomes dry carbon dioxide; after being split by the splitting device 15, a part of the carbon dioxide returns to the gas mixing device 8 through the preheater 11 to ensure the demand for recycled air volume, and the other part of the carbon dioxide is compressed, condensed, separated and liquefied and then stored in the liquid CO2 storage tank 17; the liquid CO2 storage tank 17 is used to supplement the recycled carbon dioxide flow when the primary air volume and secondary air volume increase, and the remaining carbon dioxide is recycled.

[0035] The present invention realizes the low-carbon transformation of traditional thermal power through multi-energy coupling and recycling. The system makes full use of the mine drainage water 1, a traditional waste, as the raw material for electrolytic hydrogen production, and combines the curtailed new energy power 2 to electrolyze water to produce hydrogen, realizing the efficient recycling of resources. The prepared green hydrogen can be directly used for thermal power blending, significantly reducing the carbon emission intensity of coal-fired boilers; at the same time, the oxygen by-product of electrolysis greatly improves the combustion efficiency through oxy-fuel combustion technology and creates a high-concentration CO2 environment, providing favorable conditions for subsequent carbon capture. This synergistic coupling design of electrolytic water hydrogen production and oxy-fuel combustion not only solves the problem of curtailed new energy power consumption, but also realizes the resource utilization of mine drainage water, constructing a low-cost and high-efficiency zero-carbon power production system. In particular, for the scenario of bundling large-scale wind and solar new energy bases with supporting coal-fired power, it ensures that coal-fired power has both low-carbon and even zero-carbon capabilities while providing flexibility, and improves the proportion of green power transmitted by UHV.

[0036] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flexible zero-carbon power system, characterized in that, It includes mine drainage water (1) and abandoned electricity from new energy (2); the mine drainage water (1) and the abandoned electricity from new energy (2) are both connected to an electrolytic hydrogen production device (3); the electrolytic hydrogen production device (3) is respectively connected to a magnesium-based solid hydrogen storage device (4) and an oxygen storage tank (7); the oxygen storage tank (7) is connected to a gas mixing device (8); the mixing device (8) is respectively connected to a fuel delivery device (9) and a boiler (10); the fuel delivery device (9) is connected to the boiler (10); the magnesium-based solid hydrogen storage device (4) is respectively connected to the boiler (10) and an oil-steam heat exchanger (5); the oil-steam heat exchanger (5) is connected to a steam turbine (6); the steam turbine (6) is connected to the boiler (10).

2. The flexible zero-carbon power system according to claim 1, characterized in that, The boiler (10) is connected to a preheater (11); the preheater (11) is connected to a dust collector (12); the dust collector (12) is connected to a desulfurization tower (13); the desulfurization tower (13) is connected to a dehydrator (14); the dehydrator (14) is connected to a shunt device (15); the first outlet of the shunt device (15) is connected to a CO2 compressor (16); the CO2 compressor (16) is connected to a liquid CO2 storage tank (17).

3. A flexible zero-carbon power system according to claim 2, characterized in that, The boiler (10) is connected to an economizer; the economizer is connected to the preheater (11).

4. A flexible zero-carbon power system according to claim 2, characterized in that, The CO2 compressor (16) is connected to a cooling device; the cooling device is connected to a separation device; the separation device is connected to the liquid CO2 storage tank (17).

5. A flexible zero-carbon power system according to claim 2, characterized in that, The second outlet of the shunt device (15) and the liquid CO2 storage tank (17) are both connected to the gas mixing device (8) through the preheater (11).

6. A flexible zero-carbon power system according to claim 1, wherein, The magnesium-based solid hydrogen storage device (4) is connected to the first inlet of the oil-steam heat exchanger (5) through a first pipeline; the first outlet of the oil-steam heat exchanger (5) is connected to the magnesium-based solid hydrogen storage device (4) through a second pipeline.

7. A flexible zero-carbon power system according to claim 1, characterized in that, The second outlet of the oil-steam heat exchanger (5) is connected to the steam turbine (6) through a third pipeline; the steam turbine (6) is connected to the second inlet of the oil-steam heat exchanger (5) through a fourth pipeline.

8. A flexible zero-carbon power system according to claim 1, characterized in that, The liquid CO2 storage tank (17) and the magnesium-based solid hydrogen storage device (4) are both connected to a collection device.

9. The usage method of a flexible zero-carbon power system according to claim 1, characterized in that It includes the following steps: The abandoned electricity from new energy (2) powers the electrolytic hydrogen production device (3), enabling the electrolytic hydrogen production device (3) to electrolyze the mine drainage water (1) to produce oxygen and hydrogen. According to the load and blending ratio of the boiler (10), hydrogen is preferentially supplied to the boiler (10), and the excess hydrogen is stored in the magnesium-based solid hydrogen storage device (4); when the electrolytic hydrogen production device (3) shuts down or operates at a low load and the produced hydrogen does not meet the blending demand of the boiler (10), hydrogen is released from the magnesium-based solid hydrogen storage device (4) for supplementation; the heat required for dehydrogenation of the magnesium-based solid hydrogen storage device (4) is provided by extracting high-temperature steam from the steam turbine (6) and heating the heat transfer oil through the oil-steam heat exchanger (5); the specific dehydrogenation rate is regulated by the temperature and flow rate of the heated heat transfer oil. The generated oxygen is stored in the oxygen storage tank (7) through compression or cryogenic cooling. According to the load demand of the boiler (10), the oxygen storage tank (7) supplies oxygen in a timely and quantitative manner, and mixes with the recycled flue gas in the gas mixing device (8) to form primary air and secondary air. The primary air enters the fuel conveying device (9), carries pulverized coal into the boiler (10), and the secondary air directly enters the boiler (10). In the boiler (10), according to the combustion, load and flue gas characteristics, the amount of hydrogen, primary air volume and secondary air volume participating in combustion are adjusted in real time. Hydrogen and pulverized coal in the boiler (10) burn in an oxygen and carbon dioxide atmosphere, generating high-concentration and high-humidity flue gas, which is discharged from the economizer, and after being cooled by the preheater (11), successively enters the dust collector (12), desulfurization tower (13) and dehydrator (14), and then becomes dry carbon dioxide. After being split by the splitting device (15), a part of the carbon dioxide returns to the gas mixing device (8) through the preheater (11) to ensure the demand for recycled air volume, and the other part of the carbon dioxide is compressed, condensed, separated and liquefied and then stored in the liquid CO2 storage tank (17). The liquid CO2 storage tank (17) is used to supplement the recycled carbon dioxide flow when the primary air volume and secondary air volume increase, and the remaining carbon dioxide is recycled.

10. A method for using a flexible zero-carbon power system according to claim 9, characterized in that, The recycled flue gas is carbon dioxide.

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